Quote Originally Posted by Geonz
Research bears out the experiences here: for girls, it is socially much less comfortable & healthy to be the most mature one in the class; for boys, it is more stressful to be late maturing.
I am in agreement with you there, Sue. But I just found this study which contradicts, regarding delaying Kindergarten for summer-born children. Granted, it does not address the gifted child, but it does touch upon the various maturity levels of kids.

...The USC professor was first inspired to research this matter when he faced it as a parent.
“As my first child was about to enter kindergarten, I heard a lot from parents and school officials that children with summer birthdays, especially boys, would benefit from having a ‘year to grow’ before they start school,” Painter said. “This could give them an academic advantage and prevent them from falling behind.
“I decided that I would study this and find out if there were any academic differences in the long term,” he said. “But despite the fact that these children were a year older than their comparison group, they did not do any better.”

Delaying Kindergarten Has No Benefits
09/07/06
There are few advantages for children who wait a year to enter school, according to USC and Texas researchers.
http://www.usc.edu/uscnews/stories/12716.html